Christophe Leroy wrote:
Le 24/11/2020 à 17:35, Naveen N. Rao a écrit :
Hi Christophe,
Christophe Leroy wrote:
Hi Naveen,
Few years ago, you implemented eBPF on PPC64.
Is there any reason for implementing it for PPC64 only ?
I focused on ppc64 since eBPF is a 64-bit VM and it was more straight-forward
to target.
Is there something that makes it impossible to have eBPF for PPC32 as well ?
No, I just wasn't sure if it would be performant enough to warrant it. Since then however, there
have been arm32 and riscv 32-bit JIT implementations and atleast the arm32 JIT seems to be showing
~50% better performance compared to the interpreter (*). So, it would be worthwhile to add support
for ppc32.
That's great.
I know close to nothing about eBPF. Is there any interesting documentation on it somewhere that
would allow me to easily understand how it works and allow me to extend the 64 bit powerpc to 32 bits ?
I don't think there was ever a formal spec written for the eBPF VM. Here
are a few resources which should help, alongside the existing JIT
implementations:
- BPF Kernel Internals:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/filter.rst#n604
-
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/bpf
- BPF and XDP Reference Guide: https://docs.cilium.io/en/stable/bpf/
- Naveen
